Millionaires long to be billionaires. No matter how much wealth people accumulate, they'll always want more.

This story originally appeared in The Lowdown, ABP’s weekly roundup of news, culture, holy-shit awesomeness, event updates & exclusive offers delivered straight to your inbox. Click here to subscribe.

◊◊◊

The end of the year is a time for appreciating family, friends and the comforts we enjoy. Oh yeah, and making lists of everything we want.

New research indicates the rich may have a harder time appreciating what they have, always yearning for that extra “0” on the end of their bank account balance.

It IS a competition: We humans like to size up our neighbors to judge how we’re doing in life. Studies show that when people assess their own life satisfaction, they primarily ask if they’re doing better than before and better than other people. One of the easiest ways to answer is with the hard numbers of finances.

It’s much simpler to compare cars and houses than parenting abilities or emotional well being. As the upwardly mobile increase their wealth, they still feel competitive with their neighbors and social circle, compelled to keep keeping up.

There is no ‘enough’: Satisfaction is sand through the tightening grip of the ultra-rich, according to Michael Norton, a Harvard Business School professor who has studied the connections between happiness and wealth. The more they grasp for the sum that will deliver contentment, the more elusive the goal becomes. Once they move into new economic strata, the drive for more persists.

Norton and his team asked more than 2,000 millionaires and ultra-wealthy people about their happiness on a scale of 1 to 10, then followed up by asking how much more money it would take to get to 10.